1. Field of the Invention
The present invention relates to a lens dyeing method and a lens dyeing apparatus.
2. Description of Related Art
As a method for dyeing plastic (synthetic resin) spectacle lenses, a dyeing method by dipping a lens in a dyeing solution (a dip dyeing method) has been known. This method, which has been used from long ago, has disadvantages such as poor working environments and difficulty in dyeing a lens made of a high refractive material. Therefore, the inventor of the present invention proposed a dyeing method in which dyeing inks containing sublimable dyes are applied onto a base material such as paper by a printer to produce a dyeing base body, the dyeing base body and the lens are placed facing each other in noncontact relation, the dyeing base body is heated under substantially a vacuum condition to deposit the dyes onto the lens, and the lens deposited with the dyes is further heated to fix the dyes on the lens (hereinafter, referred to as a “vapor deposition transfer dyeing method”). See U.S. Pat. No. 6,520,999B1 (JP2001-59950A), for example.
The above vapor deposition transfer dyeing method could dye a lens made of a high refractive material. However, such a lens made of a high refractive material is liable to discolor or turn yellow due to heating. This is a serious problem particularly when part of a lens made of a high refractive material is not to be dyed, for example, when the lens is to be dyed in gradations.